1. Field of the Invention
This invention relates to an odor trap for a waterless or low-flush urinal, particularly to an odor trap with a cup-shaped housing that has an inlet located on an upper end and an outlet located on a lower end, with a siphon that blocks the passage of gas from the outlet to the inlet and with a urine collector in the shape of a funnel.
2. Description of the Related Art
Odor traps of this type have been known for a long time. They have the significant advantage that the urinal requires no water connection and no flushing device or that the urinal requires only a little water. In such urinals, however, it is difficult to guarantee the necessary hygiene and to completely prevent the occurrence of unpleasant odors. The prior art suggests numerous solutions to the problem. In WO 97/15735, for example, an odor trap is disclosed in which there is a sealing layer that consists of an oil. U.S. Pat. No. 5,711,037 teaches an odor trap in which a cup-shaped float is inserted in the inlet, which float is closed on top and open on the bottom. WO 99/57382 discloses an odor trap in which, below the inlet opening, there is a spherical float which floats in the collected urine and thereby closes the opening. During use, the float briefly opens the opening so that the urine can flow into the siphon. One problem with this odor trap, however, is that a residue of urine always remains above the float, which contributes significantly to the occurrence of an unpleasant odor.
The object of the invention is to create an odor trap of the type described above which is characterized by an even lower propagation of unpleasant odors and is also more reliable.
The invention teaches that this object is accomplished on an odor trap of the type described above wherein the inlet funnel empties into an open tube that has a relatively small inside diameter, and that on the lower end of the tube there are surfaces for the condensation of the odorous substances that are given off. The tube with the relatively narrow inside diameter reduces the ascending air current which carries the odorous substances. Before the odorous substances that are produced can enter the tube, they condense at least partly on the above mentioned surface. The quantity of odorous substances is therefore largely retained by the above mentioned surfaces and the condensation on these surfaces as well as by the minimization of the passage opening. Tests have shown that the condensation is particularly effective when the above mentioned surfaces are realized in a shape similar to that of an Erlenmeyer flask. Alternatively, hemispheric surfaces are also suitable, along which the exiting air must flow and on which the odorous substances produced condense at least partly. In one development of the invention, the generation of unpleasant odors is suppressed particularly effectively if an additional siphon that has a relatively small surface area is located above the main siphon. The effect is further enhanced if two or more such siphons are arranged in a cascade fashion.
In one development of the invention, the odorous substances are extracted above the main siphon by means of a fan. In a development of the invention, the odorous substances extracted are transported to the drain line. The extracted air can also be cleaned in a filter, for example by means of activated carbon or with catalytic deodorization. The formation of odors in the body of the urinal itself can then be prevented, while in one development of the invention, the extracted air is introduced into the urinal body so that it flows downward on the inside of the urinal body into the inlet of the odor trap. Odorous substances in the urinal body are then carried along by the air and can be removed in a filter.
Additional advantageous features of the invention are described in greater detail in the dependent claims, in the following description and are illustrated in the accompanying drawings.